Leopold BloomThat's entirely dependent.
I haven't watched the video you guys are talking about, but the thing is, you've mentioned 'how it relates to life in which that poem was written' (so basically context). Unless this was the boy's chosen poets, the likelihood is that the exercise was a prat crit knowing Cambridge and thus, a knowledge of context isn't exactly what the admissions tutors would be looking for. Seeing 'the connections in the poem with Shakespeare and Wandsworth', who I presume is Wordsworth's internet alter-ego is a huge cop out. How do you know there are any connections? How do you know you could identify them? Is it even relevant to what the admissions tutors are asking?
You then say that you 'would have inferred about what was happening in the poem'; well duh. I don't know why you used 'inferred' at all, but firstly, some poems are ridiculously complex to understand. I actually misinterpreted a relatively simple poem in my interview, it's not quite as easy as it sounds. However, that's something that can be learned in about two minutes or less of teaching. What matters is not that you understand the poem's subject matter, but how you respond to it.
Finally, while metaphors are the most renowned and accessible literary technique, they are by no means the only ones, far from it. Someone talking about the ambiguity of metaphors, as if it were a foregone conclusion, would probably not go down brilliantly. Some poems don't have elaborate metaphors, some don't have ambiguous metaphors and some poems don't have metaphors at all.
As I said, I haven't watched the video, so I don't know if I've just spouted out a load of rubbish in relation to the actual video, but the interviews themselves are a different kettle of fish. For example, I'm sure biologists would be expected to know about fair tests, which is just common sense, and may just have been a warm up questions. The actual questions would no doubt have required actual specialist knowledge for biology and not just common sense.
I didn't mean that to sound like a vitriolic rant against you, it was really just some guidance. If indeed, you haven't started your GCSEs, then there's nothing to get worried about - it just seemed a little patronising that such a young student considers himself ready for an Oxbridge interview already, when the reality is that each interview can vary massively.
I must add, lest I get negged again (as I did for a joke in the 'hairdresser's thread a week or so back in this forum), that this was not meant to be a tirade against you im so academic and I hope I haven't come across as harsh or arrogant (I am certainly not a master of interviews).